How can we know what is the perception of customer about the product & services we provide them?

There are multiple ways that you can access this kind of informaiton and one of the most effective methods is by directly speaking to the customer  - this could be their through surveys, personal invterviews, focus groups and so on.

Remeber, what the customer perceives is actually digging into their feelings and emotions about the product. Through your findings, you can draw up a percpetion map and find out were you stand verus competitors and where the opportunities exisit in the market 

hope this helped